Day case surgery is expanding in the UK and is the favoured approach to elective surgery by the Government and patients alike. However studies have revealed patients' experience unacceptable postoperative pain when they return home after day surgery, leading to a variety of negative consequences, stemming many years, affecting many lives, with emotional and financial cost. It is imperative that pain is adequately controlled following day surgery to reduce these consequences and ensure the potential of day surgery is reached. Previous research has investigated barriers to pain management in this area, one barrier that has received little attention is that posed by the patient, and it has been suggested that patients may not utilising their analgesics appropriately with papers calling for further research in this area. Employing Interpretative Phenomenological Analysis (IPA) this study explored patients' use of analgesics on returning home following day surgery. Using IPA for analysis, interviews with twenty eight patients revealed many to avoid analgesics enduring severe postoperative pain during their recovery, and provided new understanding showing patients' use of analgesics to be as a result of a complex intentional decision making process based on a matrix of beliefs they held surrounding pain, analgesics and day surgery. These beliefs were found to be influenced by past experience, and cultural context, with this research being the first to identify many of these beliefs and make further sense of them by producing an explanatory framework illustrating how they exert their influence upon patients' decisions regarding analgesic use. One implication of these findings is that day surgery is not as straightforward as suggested, and simply providing patients pain management information and effective analgesics underestimates the complexity of the patient's experience when they return home. Further research is now required to identify alternative ways to reduce pain following day case surgery. One recommendation is to overcome erroneous beliefs held by patients. In particular the explanatory framework produced by this research provides a unique insight into the mechanism by which these beliefs may exert their influence upon patients' analgesic use, and may prove a useful tool to achieving this, overcoming pain and its negative consequences, paving the way for day case surgery to reach its full potential.